介绍了直缝埋弧焊缝在线超声波自动探伤对于横向裂纹缺陷采用一字型扫查探伤方法的工作原理和功能及其探头布置与声程选择、对比样管与人工缺陷的选择方法。通过探伤实例分析,在线超声波自动探伤设备选用射流(水柱式)耦合一字型扫查焊缝及热影响区处横向裂纹缺陷,探头入射角选用18.9°,水柱高度约10mm为宜,声程采用3、4次波法。可有效检测出直缝双面埋弧焊中的横向裂纹缺陷,保证钢管焊缝内在质量。 This paper introduces the working principle and function of on-line ultrasonic flaw detection of transverse seam submerged arc welding and the method of selecting the probe layout and sound path, the comparison of the sample tube and the artificial flaw. Through the analysis of testing example, the on-line ultrasonic automatic testing equipment selects jet (water column) coupled with in-line scanning weld and transverse crack defect in heat-affected zone. The probe angle of incidence is 18.9 ° and the height of water column is about 10mm. 3,4 times wave method. Can effectively detect the vertical cracks in the double-sided submerged arc welding defects in order to ensure the inherent quality of the weld pipe.